#include <Keypad.h>

const byte ROWS = 4; // Number of rows in the keypad
const byte COLS = 4; // Number of columns in the keypad

// Define the Keymap
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

// Connect keypad ROW0, ROW1, ROW2, and ROW3 to these ESP32 pins.
byte rowPins[ROWS] = {32, 33, 25, 26}; // Connect to the row pinouts of the keypad
// Connect keypad COL0, COL1, COL2, and COL3 to these ESP32 pins.
byte colPins[COLS] = {27, 14, 12, 13}; // Connect to the column pinouts of the keypad

  Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Pin connected to the LED
const int ledPin = 2; // Adjust pin number as per your setup

// Variable to store the LED state
volatile bool ledState = LOW;

// Interrupt flag
volatile bool interruptFlag = false;

void IRAM_ATTR isr() {
  interruptFlag = true;
}

void setup() {
  // Set LED pin as an output
  pinMode(ledPin, OUTPUT);
  // Initialize keypad
  Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
  // Attach interrupt to pin connected to the keypad "D" key
  attachInterrupt(digitalPinToInterrupt(colPins[3]), isr, FALLING);
  // Initialize serial communication
  Serial.begin(9600);
}

void loop() {
  // Check if interrupt flag is set
   char key = keypad.getKey();
    Serial.println(key);
  if (interruptFlag) {
    // Toggle LED state
    ledState = !ledState;
    // Update LED
    digitalWrite(ledPin, ledState);
    // Print a message to Serial Monitor
    Serial.println("LED Toggled");
    delay(100); // Debounce delay to prevent multiple detections for one press
    // Reset interrupt flag
    interruptFlag = false;
  }
}